Communication processing systems and the like have been proposed that detect a data transfer rate based on received serial data and perform sampling at an optimal frequency depending on the data transfer rate (for example, refer to Patent Literature 1 and 2).
For example, a communication processing system disclosed in Patent Literature 2 detects a data transfer rate based on a communication signal and generates a sampling clock depending on the detected data transfer rate. Furthermore, this communication processing system selects, among multiple sampling filter circuits with different frequency characteristics, a sampling filter circuit depending on the detected data transfer rate, and performs sampling at an optimal frequency depending on the data transfer rate of an input signal.